Expect extra office visits to monitor thyroid patients

Poor thyroid function can be treated through several drug choices. Hypo-thyroidism (hormone underproduction) is generally treated with levothyroxine (LT4). Hyperthyroidism (hormone overproduction) is generally treated with a thionamide medication such as methimazole or propylthiouracil (PTU).

Two hormones, T3 and T4, are produced by the thyroid gland.

"In a study of 50 euthyroid patients who underwent thyroidectomy and then received LT4 monotherapy for replacement, serum T3 concentrations after thyroidectomy were equivalent to those before surgery, indicating that LT4 monotherapy leads to adequate serum concentrations of T3," says Mark Abramowicz, MD, editor-in-chief of The Medical Letter on Drugs and Therapeutics, a non-profit newsletter that critically appraises drugs.

"When we first prescribe the medication, we check patients more frequently," says Peter A. Singer, MD, director of the Thyroid Diagnostic Center at the Keck School of Medicine at the University of Southern California, and a member of the board of the American Association of Clinical Endocrinologists. "Once patients are on an established dose of levothyroxine, monitoring is only necessary once a year unless something changes."

Alan P. Farwell, MD, director of the Endocrine Clinics at Boston Medical Center, says in his experience, when MCOs change the preferred brand of levothroxine on their formulary, they incur substantial increased costs because of additional office visits associated with members' medication changes.

Physicians don't experience similar problems with changes in brands of statin medications, for example, because a 15% change in potency of statins doesn't have a significant effect on the patient.

"I've been doing this for 25 years, and I've observed that each time the MCO changes to a different brand of levothroxine, the patient has to come in again for at least one extra visit," Dr. Farwell says.